With regard to the technical field with which the present invention is concerned, several types of different electrical connectors are known to the art, these electrical connectors and the electrical contact devices associated therewith, for instance male and female contacts, are normally adapted for a chosen specific application.
With regard to features specific to the present invention and also to the specific technical field of the invention and the object of effective electromagnetic screening and earth potential relationship, it can be mentioned that electrical connectors are known to the art which include a cable connecting part and a circuit-board connecting part, and where the metallic casings of these connecting parts function as an electromagnetic screen and are earth-potential related, and also include means for giving the casings of respective connecting part a common potential, such as a common earth potential when said connecting parts mutually coact.
Such effective screening is necessary because modern electronic systems often utilize signals of very high frequencies and bit rates. It is to be expected that still higher frequencies and bit rates will be used in the future.
Practical tests have also shown that from the screening aspect, the weakest points are the necessary connecting points between external conductors and the circuit boards mounted in a circuit-board magazine. The connections are effected with electrical connectors connected between one or more circuit boards and external cables or conductors.
Examples of the earlier standpoint of techniques are found in prior publications EP-A1 0,370,833, 0,430,105, 0,467,400, 0,512,438, 0,561,497, 0,524,426, U.S. Pat. No. 4,420,793 and WOA1 87/07441.
These publications teach the use of hole-mounted screening casings connected with the earthing plane of respective circuit boards.
An electrical connector means of this kind also requires the circuit board to have earth-potential related electrical contact means on the edges thereof, so that electrical and mechanical coaction can be achieved with a circuit board related connecting part of the casing.